1. Field of the Invention
The present invention relates to a touch controlled apparatus and a method thereof, in particular to a multi-touch controlled apparatus and a method thereof.
2. Description of the Related Art
Touch panels available in the market can be categorized into two main types, respectively: a resistive touch panel and a capacitive touch panel according to their physical properties. The resistive touch panel generates a voltage signal when it is touched gently by a finger or any other similar objects, and the capacitive touch panel makes use of a tiny current of the finger (which is generally used in the touch panel of a laptop).
The outermost layer of the resistive touch panel is a polyester film, and a conductive metal coating is coated onto an internal side of the polyester film. And, the lowest layer of the screen is a glass plate coated with an electrically conductive material and attached onto a cathode ray tube (CRT) or a liquid crystal display (LCD). A layer containing separation dots and made of polyester is used for separating the glass plate and the polyester film. A pair of controllers is disposed in the direction along the X-axis of the glass plate and the Y-axis of the polyester film respectively. And, a tiny voltage gradient is applied thereto. If a screen is touched by a finger or a touch pen, then the two conductive layers will be pressed together and forms a touch point, and an electronic device can detect both of the X-coordinate and Y-coordinate of the touch point.
In general, a conventional touch panel having a multi-touch function is a capacitive touch panel adopting a complicated circuit. Both sides of the glass plate of the capacitive touch panel are coated with an electrically conductive material, and a scratch resistant coating is coated onto an external side of the glass plate. A uniform low-voltage electric field will be produced on the external conductive layer by the electrodes around the glass plate. The internal conductive layer can provide an electromagnetic interference (EMI) shielding to reduce noises. If the screen is touched by the finger, a capacitive coupling will be produced to absorb the tiny electric current of the finger by the electric field formed at the external conductive layer. Each electrode is responsible for measuring the electric current coming from each corner, and the controller determines the coordinates of the finger. Therefore, the electric field is changed to produce the capacitive coupling if the capacitive touch panel is contacted by the electrically conductor, and the current can be detected to determine the touch position. The capacitive touch panel simply depends on a contact of a human body or a tool having an electrically conductor to change the current to achieve the touch function that a general stylus fails to achieve.
Unlike the capacitive touch panel, the resistive touch panel can achieve a single touch only, but not the multi-touch function, due to the structure of the resistive touch panel. With reference to FIG. 1 for a flow chart of a conventional single touch method, the single touch method comprises the following steps:
In Step S11, a touch controlled display interface is touched by a user. In Step S12, a first position signal (a coordinate) is generated to represent the first position by an analog-to-digital converter of an encoder/decoder (or codec). Step S13 it is determined that whether or not the user leaves the touch display interface. If yes, then Step S14 the touch display interface waits for being touched for another time, or else, the procedure returns to Step S12.
In view of the aforementioned shortcomings of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally developed a multi-touch controlled apparatus and a method thereof as a basis to overcome the shortcomings of the prior art.